Then it dawned on me; look at what “it” is wearing! That pattern! A dwarf-looking pattern, if I am any judge (and I’m not, but it’s my blog so humor me!) What other race would wear something with those particular shapes in the fabric. It looks distinctly like worn velvet, and reminds me more than a little of the velvet surcoat Thorin wears.
Now, let’s look at those worn rags again. They were not always rags, and from what we have seen of LOTR creatures, no orc or goblin would be wearing something so civilized. So perhaps this creature is actually a dwarf. I’m going to throw out the possibility that velvet would only be worn by those of a noble house, and why not the house of Durin itself?
Thrain II has already been cast (actor Mike Mizrahi) and should be appearing somewhere in the films, but there are many possible places, as Thorin’s father was present for the coming of Smaug, and the battle of Azanulbizar. But he was also the one to give Gandalf the iconic items which the wizard later bestows upon Thorin.
In The Hobbit, Gandalf explains to Thorin:
“Your father went away to try his luck with the map after your grandfather was killed; and lots of adventures of a most unpleasant sort he had, but he never got near the Mountain. How he got there I don’t know, but I found him a prisoner in the dungeons of the Necromancer….I tried to save your father, but it was too late. He was witless and wandering, and had forgotten almost everything except the map and the key.”
Thrain was supposed to have been taken to the pits of Dol Guldur, so Sauron could take back the ring of power. There he was driven mad, and did not know himself by the time Gandalf found him. He had also been blinded in one eye during the battle of Azanulbizar, and though we can’t see very close here, there is a nasty old scar running down the side of his head. Check out this post for a detailed biography on Thrain.
In this last shot, he appears more like a bearded man (or dwarf) than any creature. It is hard to tell if the person in question is of dwarf height, compared to Gandalf, but if he is, could this horrid wretch be King Thrain?
Although not very flattering, there is a sort of similarity to Thorin, with long dark hair, and deep set eyes. We assume that Thrain was withered away to nothing due to long imprisonment and torture, but the book really does not specify. So a death brought on by a mad rage may be possible too.
But despite this, the timing may not be correct. I do not see Glamdring in this fight scene, but it is in several other frames before it, which appear to take place in a similar looking area. If Gandalf has the sword here, then this should not be Thrain, unless they have altered the times, or story-lines, drastically (which is not unheard of).
Keep in mind, I have not had time to check other blogs to see if this has already been hashed out. These are just my observations and conjectures.